When playing back music with DVD (Digital Versatile Disc) players, CD (Compact Disc) players, or MD (Mini Disc: registered) players, it is very important to play back music with high quality. The same applies to playing back music compressed using ATRAC (Adaptive Transform Acoustic Coding: registered) or MP3 (MPEG-1 Audio Layer-3) since users eventually listen to time-series signal waveforms transformed from the compressed music.
In contrast, a device that can change content, such as music, in real time in accordance with a current situation of a user is now being considered. For example, the tempo or pitch of music is changed in accordance with a current situation of a user and short sections of music materials are spliced to create one piece of continuous music. From this point of view, the device plays the role of improvising a new piece of music by combining existing pieces of music, which is conventionally conducted by a DJ (Disk Jockey) or VJ (Video Jockey).
When people enjoy music in a concert hall or a discotheque, they stamp, jump, or move their heads back and forth. Swinging in tune with music is not uncommon. Just walking in tune with marching music is pleasant and uplifts your spirits. This proves that synchronizing the rhythm of your physical movements, such as stepping or movement of your head, with the rhythm of content can enhance your spirits or feeling.
According to the invention disclosed in Japanese Unexamined Patent Application Publication No. 2000-300838, in a step game (music direction game), such as “Dance Dance Revolution” (trade name), in which players compete to get a score by stepping in tune with music, play environments that match players' tastes are provided.
According to the invention disclosed in Japanese Unexamined Patent Application Publication No. 2002-65891, the above-described step game is applied to rehabilitation of patients. In this game, the heart rate of a user (patient) is detected and, if the detected heart rate exceeds a reference heart rate, an alarm is issued.